Internal-combustion engine.



APPLiCATiON LED OCT. M, HIE- SHEETSSHEET I.

INVENTOR WITNESSES E. GIDDINGS, JR. INTERNAL COMBUSTION ENGiNE APPUCATION FILED OCT- I4, l9l5.

Patented June 26, 1917.

2 SHEETS-SHEET 2.

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I T all whom it may concern:

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' CHARLES E. G1DDINGS,'JE., or PITrsBURGii, PENNSYLVANIA.

' INTERNAL-COMBUSTION ENGINE.

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Be it known that I, CHARLES E. GIDDINGS, Jr a citizen of the United States, residing at Pittsburgh, in the State of Pennsylvania, have invented certain new and useful Improvements in Internal Combustion Engines, of which the following is a specificatlon.

My invention relates more particularly to four-cycle gasolene engines, and its primary objects are to efficiently scavenge the engine cylinders of burnt gases; to introduce the gas in a manner to more evenly distribute the heat and secure more perfect combustion, and to remove the burnt gases in a manner to flush and clean the cylinder and promote efiicient cooling. I have illustrated the invention in a preferred form in the ac companying drawings, in which Figure 1 is a central vertical section of one of the cylinders of a pair, taken on the line (1-1) in Fig. 2; Fig. 2 is a side elevation of the engine casing and .pair of cylinders, taken at right angles to the view of Fig 1; Fig. 3 is a horizontal section along the line (33) in Fi 2. C)

Internal combustion engines most frequently having a single exhaust port for the burnt gases, with the'result that that part of the cylinder and casing contiguous to the exhaust portis hotter than other parts. Also it is customary both in two-cycle and higher cycle engines, to begin the exhaust of burnt gases before the piston reaches its extreme position in the power stroke; and again the inlet and exhaust valves are usually opened gradually. I have found a greater efiiciency attained by arranging a very large lntake valve in the center and opening it suddenly; by providing a plurality of symmetrically placed outlet valves and opening them suddenly; and by partly compressing the burntcooling chambers (9-) and at the top the casing has anv enlarged space (10). The cylinder casing and combustion chamber (10) are supplied with-gas through a valve Fig. 3, which ports are closed the ex haust valves 20, 20*. These valves are on stems 21, 21 normally held down by helical springs 22, 22 as shown.

I preferably mount in the casing 4 a pair of shafts 23, 23 on which are placed sprocket v wheels 24;, 24 driven with a one-half-to-one speed ratio from the engine shaft 5 by means of chains 25, 25*. On the shafts 23, 23 I place cams 26, 26. to operate the exhaust ports by engagement with rollers 27, 27 on the bottoms of the valve stems 21, 21". (It will be understood that there area pair of these exhaust valves for each of the cylinders, as shown in Fig. 3.)

Conveniently on one of the same shafts 23 I provide for each cylinder another cam 28 operating a plunger 29, which by means of bell-crank lever 30 pinned to the stud 31 on the cap 17, operates to depress stem 15 of the inlet valve 13,.using an adjusting screw 32 to adjust the lag in the operation. The cams 26, 26 are arranged to impart to the stems 21, 21 a rapid rising motion when the piston 11 has made about one-sixth of its upward travel, and to drop the valve rods still more suddenly at the position of extreme elevation of the piston. The cam 28 likewise opens the valve 13 when the piston is within one-sixth of its travel from the uppermost position, and closes the valve when the piston is at its extreme lower position.

Supposing the engine (as here designed) to be a four-cycle engine, it will be under- Patented June 2c, 1917.

Application filed October 14, 1915. Serial No. 55,802. i

I 13 normally held up by coil springl l en- I stood that shortly after the piston 11 has begun its induction stroke, the inlet valve 13 is positively and quickly opened, and on account of its location it distributes the gas centrally through the combustion chamber.

On the next up stroke of course the inlet valve 13 is closed, and the gas is compressed. It is ignited, preferably by two sparkers 33, 33, when the piston comes within about once sixth of its stroke from the upper limit of its stroke; and there follows the working stroke downward. The exhaust valves 20, 2O are not opened immediately upon the finish of this power stroke, butthg piston will rise again preferably about one-sixth of its travel and compress the burnt gases, before the valves 20, 20 are opened. The result is a thorough flushing of the combustion chamber, and it will be noted that the burnt gases pass out symmetrically; this, together with the central location of the inlet valve, results in distributing the heat venly through the combustion chamber. T e outlet ports being large, and at a considerable distance from the cylinder walls, they promote efiicient cooling of the parts bfy providing a larger space than heretofore or escape of hot gases, and the heat is not concentrated in the working part of the cylinder as is the case where the exhaust port is directly through the wall of the cylinder. I regard this as one of the important features of my invention, and have found by experiment that the gain in efficiency more than offsets any loss of power involved in compressing the burnt gases.

Having thus described my invention and illustrated its use, what I claim is the fol lowin 1. l ii an internal combustion engine, the combination of a casing having a cylinder, a piston, an inlet port of large area centrally located over the piston and a plurality of exhaust ports of large area in the casing symmetrically placed around the cylinder,

substantially as described.

2. In an internal combustion engine, the combination with a casing having a cylinder, a piston in the cylinder, a centrally located inlet port of large area and a plurality of symmetrically arranged exhaust ports, of;

CHARLES ernniues, JR. 

